Current research projects /Completed research projects /

Cluster headache: understanding the causes

Project details

Dr Emer O'Connor
UCL Queen Square Institute of Neurology
Research area
Cluster headache
Funding type
PhD studentship
Awarded in
March 2017


Dr Emer O’Connor was awarded a Brain Research UK PhD studentship in 2017 to enable her to pursue her research in cluster headache.

Emer obtained her medical degree in Dublin in 2012 and cultivated an early passion for neurological research as a junior doctor. She first encountered patients with cluster headache when participating in outpatient headache clinics and was struck by the terrible impact of the disorder on the lives of those affected.

Prior to the award of this studentship, she spent a year working as a clinical research fellow at UCL Institute of Neurology, one of the world’s leading training centres for neurology. During this time she assembled a large series of cluster headache patients, who are now central to her PhD project.

‘The suicide headache’

Cluster headache is a rare headache disorder characterised by recurring bouts of excruciating headaches on one side of the head.

It has been described as one of the most painful conditions known to man, with the intensity of the pain often reported to give rise to suicidal thoughts.

Cluster headache impacts heavily on the lives of patients. The all-consuming pain and unpredictability of attacks can make it hard to carry on a normal life.

There are a number of different treatments that aim either to stop the pain during an attack or to stop the onset of attacks during a cluster, but there is no cure. Cluster headache remains a devastating and debilitating condition.

Emer recalls her first experience with cluster headache: 

I was called to the ward one night because a gentleman was having a cluster episode and I will never forget how horrific it was. I had never seen anyone in that much pain in all my life. It was just horrific to see someone suffering in that way - he was screaming and banging his head off the wall, and crying and crying.
They say that cluster headache is the worst pain that you can possibly experience, and I didn't quite believe it until I saw that. My heart just broke for him. And this was something this gentleman had been going through on a nightly basis for weeks and weeks and weeks, whilst trying to provide for his family, be a father, a husband, and just live a normal life.
And people don't understand, an awful lot of the time they think ‘You have a headache, what’s the big deal?’ They don't understand how debilitating this condition really is.

Read more: Cluster headache

What causes cluster headache? 

The causes of cluster headache are unknown. This severely limits our understanding of the disease and the development of effective treatments. In order to work towards a cure, we first need to understand what causes the disorder.

People with close relatives with cluster headache have an increased risk of developing it themselves, suggesting an underlying genetic cause.

A number of genes have so far been examined but without conclusive results.

Through collaboration with headache specialists internationally, Emer and colleagues have already assembled a set of more than 100 families with cluster headache, creating a biobank of DNA for further analysis.

In addition, Emer is part of an international collaboration that is in the process of collecting DNA from around 5,000 patients with cluster headache worldwide.

This collection of cases is the first of its kind and encompasses the largest cohort of cluster headache families described to date. As such, the project has the scope to produce ground-breaking insights into our understanding of this complex condition.

During the course of this study, and using the assembled cohort of patients and families, Emer will further examine the heritability of cluster headache and aims to identify and examine the genes responsible. She will carry out functional studies on identified genetic variants to examine their role in the disease.

This work is really important when you consider that up to 20 per cent of patients can be unresponsive to conventional treatments, so if we could understand what genes are involved, it would give us the knowledge to perhaps provide more targeted treatments in the future.

- Dr Emer O'Connor


This study will develop a resource for both scientists and clinicians that will stimulate and underpin ongoing research in this field.

The cluster headache DNA sample bank will act as a crucial open access resource for future studies in this area.

The genetic analyses and functional studies will aid the design of potential new therapies, helping to create a framework for future studies of the mechanisms of cluster headache and enabling the stratification of patients for future clinical trials.

These developments will ultimately lead to more effective management and an improved quality of life for people with cluster headache.

The project addresses a major knowledge gap concerning a disease that is rare, but has a strong negative impact on the lives of sufferers and their families.

- External reviewer.

Related projects

Headache and facial pain is one of our current research priorities, reflecting the large unmet need in this area. Our aim is to fund research to advance understanding of the underlying causes and mechanisms of headache and facial pain, and help advance diagnosis and treatment.

Other research projects currently funded under this theme:

Related projects

Find out about our other research in this area: